My boat wiring question is:
I have a 1979 37′ O’Day sailboat, with an Aft Cabin with the original 4 breaker terminal mounted on the locker.
When I bought the boat in 2000, I replaced the existing Loran with radar and wired it into the panel where the Loran had been and added a VHF radio to the back of the panel. Both have individual fuse protection.
Everything has worked fine until a few weeks ago when I noticed I have no power to the panel – cabin lights, engine room light, radar, radio, and autopilot do not work.
Both the positive and negative lines from the main power source in the forward part of the boat were tested by me and tested good.
I was told that it could be a ground problem. I looked at the negative marine electrical bus bar inside the locker and what is there are the negative wires from the accessories and the negative wire from the main bank in the forward part of the boat. There was also another 10 gauge wire but not attached to anything.
Should there be a ground wire attached to the buss bar to the engine and could this wire be my problem in that it somehow become disconnected?
I installed a new six breaker panel replacing the original; I installed a new 30 amp terminal (6 terminals) inside the locker and ran each accessory positive to it and then from there to the panel; Each accessory negative goes directly to the to the bus bar along with the 10 gauge negative wire from the main power source. The new panel has a negative bar which I also attached to the bus bar.
I then turned on each switch and they all light up meaning power is there. But when I turn on any of the accessories at the actual device they do not work and all the panel lights go off. When I turn off the individual accessory the panel lights will go back on. This happens with each item- cabin lights, engine room light, radio, radar, auto pilot.
Can you help me?
The problem is either in the feed wire or the ground wire.
The best way to find your problem is to test voltage levels when the system is under a load.
The panel indicator lights will initially turn on because the low current draw of the lights induces a small voltage drop in the wire. When you turn on a higher draw device, the voltage drop increases and the light turns off.
You will probably find a bad cable connection or hidden splice.
Hope this helps,
Thank you for your response.
While waiting to hear back from you, I continued to investigate the problem.
Although I found numerous other problems as the O’Day has the original wiring, the cause for the failure was due to corrosion inside the positive wire where it entered into the front panel for power. As I tried to pull the wire to locate it, it broke off and was corroded inside the insulation. The joys of an old boat.
I have rewired the entire aft by replacing all the wires and panel and everything is back in order.